Pictured below is my 50A plug that is being installed on the rear panel of my bus, basically above my drive wheels.

Anyway, what wire goes where? I should have two hot wires (probably never use one of them) and a neutral and a ground.

The receptacle is labeled:"X" on the left in the picture, all alone (Purple)"Y" top right (Black)"G" Center right (green)"W" Bottom right (white)

Also, need a refresher, I have a bare ground and an insulated neutral? or the other way around? I don't remember the terms for ground and neutral. I know, they're different, but they go the same place at the end of the day.

Second, when I'm on just 30A, what hot is being used, and what is left alone?Thoughts?

Dave

« Last Edit: February 16, 2014, 03:49:46 PM by Tikvah »

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1989 MCI-102 A3DD 6V92 Turbo, AlisonTons of stuff to learn!Started in Cheboygan, Michigan (near the Mackinaw Bridge). Now home is anywhere we parkhttp://dave-amy.com/

Both hots will normaly be used or at the ready, as a 220 v appliance might be used. In a lot of boxes an even draw of amps is a liking, so both hots are split on the loads. If only thirty is available some means of connection adapter might be needed?

I'm thinking I might connect the two sides of my box through a knife-switch for when I'm on 110 volt supply, and open the switch when I'm on 220 volt supply. Does that seem to be the right thing to do?

My whole bus is wired for nothing but 110, but 220 would give me both sides of my box.

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1989 MCI-102 A3DD 6V92 Turbo, AlisonTons of stuff to learn!Started in Cheboygan, Michigan (near the Mackinaw Bridge). Now home is anywhere we parkhttp://dave-amy.com/

How do you plan to wire your breaker box? If you are wiring it for 240v, you will have the two hot wires going to different lugs on the panel, each one energizing one side. Therefore, when plugged in to 240v, everything works. The 30A to 50A adaptors you would have to use energize both of your 50A wires, so you do not need to make any special system for it. However, instead of having two 50A legs creating 120v and 240v, you then have 30A split between two legs of 120v only. This would mean that your 120v equipment works, but any 240 stuff won't.

There is an alternative whereby you use only one of the 50A wires and have some way of jumping it to cover both legs. You would then have 50A at 120v split between both legs. I have done this on my last bus, and my present one came that way too. We do not have any 240 appliances so it works fine for us. One benefit of this is that your shore cable is 25% lighter. Obviously, this is no good if you have an electric stove, or expect to be running more than 50A worth of equipment at a given time. Three AC's would be almost there.

Do most rv campgrounds have 50 amp now?, I dont have a clue I just remember ages ago they had 30s and with that they are always 2 hots so capable of 220v to power both legs of a electric box.good evening to you all

I have my bus wired straight 120vac. Hence, I only use one side of the 50amp plug, for 50amps at 120vac which is enough to run 2 A/C's with power left over. Then with the generator, don't have to worry about balancing the loads from side to side. Good Luck, TomC

As indicated already, if you use a commercial dogbone (dogleg??) adapter to connect you 50 amp 240v connection to a 30 amp 120v outlet, the adapter will cross the hot wire to both 240v hots in your cord, so both sides of your breaker box will be hot, but on the same phase. Most buses don't have 240v appliances, so this is typically not a problem. However, as also pointed out, you will have only 30 amps available, period, which is now split between both legs of the panel, and shared by every circuit.

There are some issues with this if you use an inverter and want to power both sides of the breaker box when on battery power. Many avoid this by only using one side of the 50 amp line. Others, like myself, find more creative ways to get around it.

Craig- A little hijack here-- I would be interested in your creative solution to the inverter issue since I have been known to forget to turn the water heater off before switching to the inverter. I have considered using a sub-panel, but have been managing with putting reminder markers on the switches. Sorry

I'm thinking I might connect the two sides of my box through a knife-switch for when I'm on 110 volt supply, and open the switch when I'm on 220 volt supply. Does that seem to be the right thing to do?

NO! NO! NO! Don't do it! All it will take is one forgetful moment & a 50 amp site & both you & your bus can be toast!!

First, decide: How many amps does you bus need? If you only need 30 amps for now & future use, Just wire for 30. If you think you may need a 50 amp service later, wire for 50. Then, buy the 30 to 50 converter from WalMart!!!! It's only about $30. That will safely connect both legs of your 50A service when you only have 30A available; AND you can't forget & screw that up!!!

As an aside, I have learned to carry 50 to 30, 30 t0 20, 30 to 50, and 30A & 50A extension cables. That way I can connect to whatever. I just have to limit my usage to whatever is available.

Craig- A little hijack here-- I would be interested in your creative solution to the inverter issue since I have been known to forget to turn the water heater off before switching to the inverter. I have considered using a sub-panel, but have been managing with putting reminder markers on the switches. Sorry

Lin, on the advice of others I used a sub panel on my old MCI. The main feed from the transfer switch feed the main 100A panel. I used that size panel so I would have enough breaker spaces. Everything that had to be fed BEFORE the inverter went to this panel. The inverter is also fed from this panel. Then, this inverter feeds the sub panel. All inverter loads are fed from the sub panel. Simple & effective.

Craig- A little hijack here-- I would be interested in your creative solution to the inverter issue since I have been known to forget to turn the water heater off before switching to the inverter. I have considered using a sub-panel, but have been managing with putting reminder markers on the switches. Sorry

Yeah, it doesn't solve that problem. That's called operator error.

I have an electric element in my AquaHot that I constantly forget to turn off. The house A/C is another one I forget to turn off. My inverter is 4000 watts, and has auto-gen-start, but sometimes that just confuses the issue. My transfer switch is built with 4 DPDT relays. It provides neutral-ground bonding, switching of the inputs, and crossover ofthe two hot wires when on 120V shore (separate when on 240V shore). I removed the schematic from my website because I got some flack for it not being "to code", but it works very wellfor my needs.

I'm with opus on this one, Dave, as a minimum, get some advice from an electrician on this. I saw you mention knife switches, open knife switches are very dangerous and are hard to cover to make them safe. Instead of knife switches, use contactors or relays.

I am strictly an amateur at electrical but have completely rewired several houses aside from the work on the buses. The way I learned was to pay a very kind and reasonable electrician as a consultant on the first house I did. It is not terribly complex; you will pick it up easily. He would point out what to do and I would call him when done for him to inspect. As suggested by others, you could save yourself a lot of headaches, time, and consequences by doing something similar.

I appreciate all the comments and helpful insight. I chuckle a bit about my use of terminology. When I say knife switch, I just mean a shut-off... or whatever the current term is. I'm a bit dull, but not to the degree yet that I would use an actual knife-switch (although it would work).

I'm a little shocked (pun intended) about all the advice to hire a professional. Really? I can build an entire bus based on some gray matter between my ears and with the help of good folks like you. But, when it comes to running four wires from a socket to my panel I need a professional? What about my plumbing? Or, worse, my batteries? You can burn a bus to the ground really fast be screwing up the battery system. Oh, and my brakes! Okay, end my rant there.

I'll try to make this simple... Everything I have is 110V. No stove, oven, or large AC system. I have a panel with breakers. There is a left side and a right side to the panel (ya, it zig zags, but lets not confuse the facts). Obviously the panel is intended for 220V systems (two 110V leads). But, since I don't need the two separate leads that make 220V, I have jumpered the top of the two rows of breakers. (ran a heavy wire from one side to the other, like two inches). Now, I have two rows of 110V all on one 110V supply wire.

This make sense so far?

So, if I was to hook up a 110V 20Amp or 110V 30Amp, or 110V 50Amp it wouldn't matter, my entire panel would be hot with 110V. BUT, if I hook up 50Amp 220V (two 110V leads) now I have a problem. My little magic jumper wire is going to blow the lid off the campground... and maybe my bus. So, I got this wild idea that if I pull that little magic jumper wire out and put a switch inline, then make sure that switch is off (open) when I have 220V supplied to the box that I will magically have 110V on both sides of the box, with 50Amp supply on both. But, when I only have 110V supply, I can turn the switch on (close) and have 110V on both sides, but only the amperage available from the one line.

With me so far?

Ok, be kind. I realize that if my brain didn't engage and the switch was on (closed) when supplying 220V that we would have issues. Yes, it can be done with a relay, but the result is the same, if the switch is closed - poof! There must be a fool-proof solution. Also, someone mentioned that the readily available RV adapters combine the lines.. is that true? If that's true, I can let the adapter take the place of my magic jumper wire and the single 110V supply will automatically go to both sides of my panel.... until I hook up my generator.

Grab your sling shot... time to throw some stones in my theory.

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1989 MCI-102 A3DD 6V92 Turbo, AlisonTons of stuff to learn!Started in Cheboygan, Michigan (near the Mackinaw Bridge). Now home is anywhere we parkhttp://dave-amy.com/

I'll try to make this simple... Everything I have is 110V. No stove, oven, or large AC system. I have a panel with breakers. There is a left side and a right side to the panel (ya, it zig zags, but lets not confuse the facts). Obviously the panel is intended for 220V systems (two 110V leads). But, since I don't need the two separate leads that make 220V, I have jumpered the top of the two rows of breakers. (ran a heavy wire from one side to the other, like two inches). Now, I have two rows of 110V all on one 110V supply wire.

This make sense so far?

So, if I was to hook up a 110V 20Amp or 110V 30Amp, or 110V 50Amp it wouldn't matter, my entire panel would be hot with 110V. BUT, if I hook up 50Amp 220V (two 110V leads) now I have a problem. My little magic jumper wire is going to blow the lid off the campground... and maybe my bus. So, I got this wild idea that if I pull that little magic jumper wire out and put a switch inline, then make sure that switch is off (open) when I have 220V supplied to the box that I will magically have 110V on both sides of the box, with 50Amp supply on both. But, when I only have 110V supply, I can turn the switch on (close) and have 110V on both sides, but only the amperage available from the one line.

With me so far?

Ok, be kind. I realize that if my brain didn't engage and the switch was on (closed) when supplying 220V that we would have issues. Yes, it can be done with a relay, but the result is the same, if the switch is closed - poof! There must be a fool-proof solution. Also, someone mentioned that the readily available RV adapters combine the lines.. is that true? If that's true, I can let the adapter take the place of my magic jumper wire and the single 110V supply will automatically go to both sides of my panel.... until I hook up my generator.

Grab your sling shot... time to throw some stones in my theory.

Yes that will work. But, again, one mistake forgetting to flip that switch & you will have major problems. That would be too much risk for me, knowing I might forget it once in the next 10 or 15 years. However, you may be way younger than me & your brain still works....

I used a standard Square D panel because you can get them and breakers anywhere at a reasonable price. You can buy straight 120V panels but they are specialty items & you will pay extra for the "marine" or "RV" names.

If you really want to do the jumper thing, just wire the bus for 30A only. Then you can't get into 220V by mistake unless you plug into somebodies welder receptacle in a shop;however, that's a whole 'nother discussion. Still, if you end up with a generator that puts out 220V, you will have to rewire. Also, lots of 110V RV generators have two 110V legs that do not make 220V across them but STILL cannot be wired together. With either generator, you would only be able to use 1/2 the capacity and generators like to have balanced loads.

On my coach, as I mentioned, I had an issue with my inverter and the 30 amp dogleg adapter because it had the two hot wires combined.

On your coach, I think that may actually be the solution you are looking for. Follow along...

Wire your coach with a 50 amp inlet. Two hot wires going to either side of the breaker panel. You have a 6/4 cable with a 50 amp plug on it for hooking into a 50 amp, 240v outlet. Both sides of the panel are powered with 50 amps of 120v. You don't care about phase because you don't have240v appliances.

If you don't have 240v available, you attach a 30 amp dog leg adapter. There's a male 30 amp plug on one end and a female 50 amp on the other. Inside this animal, the single hot input wire is split and attaches to both hot wires on the 50 amp end. Bingo. Now you have both sides of the breakerpanel powered by 120v. Of course you have to limit your power consumption because you only have 30 amps available. No knife switch, rotary switch, contactor, relay, etc. Only one 6/4 power cable, and a dog leg adapter.

Now, you get to a friend's place who only has 15 amps available. No problem. There's another adapter with 15 amp male on one end and 30 amp female on the other. Plug that puppy onto the dogleg (get it?), hook the dogleg to the 6/4 cable, and you're good to go. You have 15 amps being split and powering both sides of you breaker panel. Again, you have to manually limit your consumption.

Easy peesy, lemon squeezy.

Ok, what was your original question?

craig

By the way, hooking up to your generator is no different, if you have a female receptacle from your generator into which you plug your shore cord. If your generator provides 2 hot legs, you use your 50 amp cord, no adapter. If it's single hot, you use a 30 amp receptacle and use the dogleg adapter.

Now, if you want the generator to be wired into the system so it's automatic, then you have another problem for which we don't have enough information. Also, Idon't recall if you have an inverter in the system, and I'm too lazy to go look at the beginning of the thread, but regardless, you need to be concerned about neutral-groundbonding/unbonding. This can be handled inside the receptacles if you go with a strictly manual source selection.

Tikvah- Don't be sensitive about the suggestion to get help. The knife switch, or any switch for the matter, is a bad and dangerous idea. It is only reasonable when someone seems attached to that type of idea for others to recommend getting help.

If you do it as a straight 50 amp/240v system, as Craig outlined, it's all good. If you want to do it as a 120v system, only run one hot giving you a three wire shore cable as mentioned by some earlier. Your jumper wire will be okay then. That's the way my last bus was. The only added issue would be making sure your generator is set up for 120v only. That is also easily done.